Hi:
Upgrading (or downgrading) the Windows OS (and even using "System Restore) often breaks security programs.
In order to run best on Win 10, it is advised to upgrade to KAV2016/KIS2016, as explained
HERE
But, since you have rolled back to Win7....
AFAIK, it may be normal for Windows UAC to prompt when first running the program after an OS install.
Have you tried to perform a clean reinstall of KAV2015?
Basic steps:
- Make sure you have your valid activation code handy, just in case
- Download and save -- but do not run yet -- a fresh copy of KAV2015 from HERE, as explained HERE
- Uninstall KAV from the Windows control panel, keeping ONLY license info (or nothing)
- Reboot
- ((Should NOT be necessary, but might be a good idea: download and run the Kavremover tool, then reboot))
- Run the KAV installer, activate it, update it, configure it and reboot again
More details
HERE
Let us know how it goes,